For certain purposes it is desirable to monitor performance of an operator of a machine having a sensor for at least one operating parameter and a meter responsive to the sensor for indicating the value of the parameter or parameters. For example, it may be desirable to measure the performance of an individual who rents a vehicle or other complex machine to be sure that the machine is not abused during rental.
It is for example possible to hire a helicopter without a pilot for occasional transport or handling use. The owner of the vehicle can only demand that the individual wishing to hire the vehicle show him a license for the type of vehicle to be rented. If the vehicle to be rented is very simple and rustic, relatively simple instructions will suffice to prevent improper operation. However, if the vehicle or other machine to be hired is more sophisticated, for example in the case of a helicopter, it has proven insufficient to trust the occasional pilot's ability. It is possible to operate a helicopter under abnormal conditions or beyond its allowed limits. Such operation will cause damage or wear of very expensive parts. The damage or abnormal wear is not always detectible when the complex machine is returned to the owner.
It is known to use a recording device mounted on a vehicle, which recording device permanently records useful information for subsequently determining the way the vehicle was piloted or operated. For example, trucks are equipped with clock motor driven disc recorders including a stylus for plotting truck speed as a function of time.
It is also known to use a more sophisticated recording device, employing a magnetic tape for recording digital or analog data representative of various vehicle parameters as well as other information such as pilot's calls. Those devices are usually called "black boxes".
All of these devices have some drawbacks that are described infra. First, they are always specific for the particular type of vehicle. On the other hand, it is either possible to fraudulently modify the recorded information, for example in the case of a rotating disc, or difficult to make full use of the information once the vehicle is returned, for example in the case of a "black box". The known devices designed for use with rented vehicles require, at the time the recorded information is read, decoding or analog or digital processing of the recorded data. This decoding is difficult, requires a specialist and does not deliver direct and actual evidence against the person who piloted and rented the vehicle. The pilot who hired the vehicle may, in such a situation, contest the parameters that the owner claims were read from the device and which indicate the operating manner of the vehicle.
There has been developed a "black box"-type device especially designed to be mounted on a helicopter and which does not use a magnetic tape recording system. The device comprises a digital data loading system in a memory logic circuit. This device indicates to the pilot, during a flight, any overrunning of a controlled parameter, with respect to a reference value, and is usually played back, after a flight, to read data recorded during the flight. The devices metering the operation are mounted on the helicopter so they are accessible to everybody, especially to the helicopter pilot. If, for example, the pilot is a person who has hired the helicopter for a short time period, it is not feasible to use such a device for the following reasons:
first, the helicopter owner is never sure that the pilot has not interfered with the operation of the device; PA1 on the other hand, the pilot who has hired the helicopter cannot be assured that the values of the parameters recorded in the device represent the actual parameters read on the corresponding measuring instruments on the helicopter control panel.
A memory-type electronic circuit, while used as a data recording system, is basically the same as a magnetic tape recorder. The expected advantages are well known, resulting from the use of electronic circuits, especially integrated circuits, viz: reliability, no movable mechanical parts and therefore no wear.
To conclude, there is no previously developed device to detect the use of a general purpose transport means, permitting management of a depot of sophisticated vehicles, for example for renting purpose. In a commercial device of this type, it is necessary to combine reliability of the information collected in the device, invulnerability of stored data, ease of reading and interpretation of those data, with relative simplicity so that the device does not substantially increase operating expenses.